University of Florida has a comics conference every year, and I know a few of their English MAs & PhDs list comics as their research interests. I'm not sure what the formal avenues of exploration in comics are, but they're definitely open to the idea of comics, at least.

You might also have luck in some of the programs that favor the avant-garde, or programs at art schools: Art Institute of Chicago & Brown spring to mind as being flexible about what forms students' poetry takes, and I'm sure there are at least several others. But I have no idea how open to just comics either of them are, at least for someone who's not in the "right" department.